Motorcycle-frame and the like



G. E. BRADSHAW. MOTOBCYCLEvFRAME 'AND THE m5.-

APPLIICATID'N FILED murzu. 1920. 1,368,541 Q .'3 SHEETS-SHEET Patented Feb. 15,1921.

G; E. BRADSHAW. MOTORCYCLE FRAME AND THE LIKE.

I APPLICATION FILED JULY 20. I920- Patented Feb. 15, 192 1.

3 SHEETSSHEET 3.

UNITED STATE GRANVILLE EASTWOOD BRADSHAW, OF

WALTON-ON-THAMES, ENGLAND, ASSIGN O R TO A. B. C. MOTORS LIMITED, OF WALTON-ON-THAMES, ENGLAND.

MOTDRGYGLE-FBAME AND THE LIKE.

Specification of Letters Patent. Patented Feb. 15, 1921.

Application filed July 20, 1920. Serial No. 397,743.

T 0 all whom it may can oer n:

Be it known that I, GRANVILLE Eesrwoon BRADSHAW, a subject of the King of Great Britain and Ireland, residing at A. B, C. Motor Works, Walt0n-onThames, in the county of Surrey, England, have invented certain new and useful Improvements in and Relating to Motorcycle-Frames and the like, of which the following is a specification.

My invention consists of improvements 1n and relating to motorcycle frames (including scooters), and has for its object the prevention of bent footrests and twisted frames in the course of a fall, increased lateral ri gidity of the stays which carry the back wheel, particularly in the case of a rear sprung machine, increased protection from road dirt, decreased resistance to sliding on the ground when the machine falls over and greatly increased space for accommodating engine gear box, and other details, without the necessity of increasing the overall length of the machine. It also providesa neat and accessible accommodation for tools.

Made according to my invention the lower main tubes, which are duplex, are carried from the head stem lug more or less and the side of each tube is extended laterally to approximately the maximum Width of what would otherwise be the .footrests or footboards. They may taper from the head lug downward, and may be cross braced in any suitable known manner.

At the rear, tubes, which are still a considerable distance apart, are carried upward in a suitable manner to the seat lug, and the rear stays may be attached to these tubes, which attachment would thus be very wide and insure lateral rigidity. The attachment may be hinged for the purpose of accommodating the movement of the back wheel in the caselof a sprung rear section.

A complete undershield may be fitted be tween these two tubes, which may extend upward in front to form a mud-shield and if desired the engine may be placed laterally across the frame, and even in the case of a twin cylinder horizontally opposed engine being fitted in this position; the overall width of the tubes would still be wider than the overall length of the engine, thus preventing damage to the cylinder heads in c y This undershield maybe which may be-attached to the undershield in the form of a tray, and the tools may be prevented from shaking or rattling by any known means, as for instance, by laying a piece of felt in the bottom of the tray, and on which may be placed a piece of wood cutto the shape of the various tools.

Such type of frame would probably not require a tube under the fuel tank, which tank may be flexibly mounted on pivots in any knownmanner at the front and the back, which pivots may work at right angles to one another, or the tank may be carried on. strips of thin metal which would be flexible enough to prevent vibration and leakage. The main lower. tubes of the frame above referred to may be smooth and without projections, so that in the case of a bad fall they would form skids which w'ouldslide along the ground instead of digging into the ground as happens with the usualtype of footrest. This latter arrangement causes the machine to be brought to rest very quickly and imposes considerable stresses.

Though I do not claim any particular kind of stand, my invention enables a stand .to,

with, legs of different length so that when lowering the shorter stand it is not necessary to raise the rear wheel above the type, that is, two stands combined into one' ground when the machine is just required v to be propped up and the longer legs may be lowered if'it isrequired to rotate or remove the rear wheel. p This arrangement of, frame srivesadequate space for theinstallation of dynamos, I

batteries, etc., in a relatively low position to keep the center of gravity of the machine as near the ground as possible, and it enables the complete engine, clutch gear box, and rear drive unit to be fitted. My invention will now be more particularly describedand illustrated by means of the accompanying drawings in which:

Figure l is a plan of the frame of a motor cycle. F ig". 2 is a sideelevation of the same.

Fig; 3 is a rear end elevation of a shield for attachment to the frame. 'Fig. 4 is a rear elevation of the frame.

Fig. 5 is a side elevation of the shield, and

Fig. 6 shows the detail of a tool box and footboard as fitted in the shield.

The same reference characters apply to the same or similar parts in all figures.

Referring to the said drawings, 1 is the head stem lug to which the top bar 5 of the frame is attached. The rear end of the top bar 5 is attached to the seat h1g7, which carries also a cross tube 6. a Two main lower tubes 2 and3 are attached to the head stem lug 1, one on each side, and they are set at an angle which carries them outward, downward and backward to points 8 and 8 respectively where a cross tube 8 connects them together. The length of the tube 8 will depend on the breadth which it is desired to give the frames to provide room for, and pr0tect,the mechanism to be carriedas explained hereinafter. From the points 8 the tubes 2 and 3 are continued backward and downward, .(and inward, outward or parallel as desired), to the points 9 and 9 respectively, where they are connected by a cross tube 9. The tubes 2 and 3 are continued back approximately horizontal and parallel or converging or diverging to the 1 points 10 and 10 where they are connected by across tube 10. The tubes 2 and 3 are then continued toward the rear and when the desired length of the horizontal part of frame is completed are bent up to meet the respective ends of the cross tube 6. (For thesake of clearness in Fig. 4 only the ends of the top bar 5 are shown.) To the tubes '2 and 3 at a point below the cross bar 6 is attached across bar 11 to which the stays 12 for the back wheel are attached.

accommodate the movement of the back wheel in the case of a sprung rear section. Fig. Qindicates the position of a petrol tank 18 and. an engine with gear-box, magneto, etc. 19 inside the frame. 1

5 In Figs..3 and 5, 20 is a shield which is shaped to cover the space between the two lower main tubes 2 and 3 from the head stem lug 1 to a point below the cross tube 1l thus protecting driver and mechanism from mud and dirt. The shield 20 is fitted with These stays 12 may be hinged on the bar 11 to apertures 13 for air for cooling purposes and clips, straps or other means 21, 22 and 23 to secure it to cross tubes 10,9 and 8 respectively. a

In the sides of the horizontal part of shield, shallow tool boxes 17 are formed of which the lids 16 are the footboards.

I do not confine myself to the exact shape of the frame shown in the drawings, or to the number and dis osition of bars or tubes, or to the shape of he shield, air vents, tool boxes or footboards. I may, for instance, decide to employ more than one top bar 5 and in practice it may prove advantageous to have two of such top tubes either parallel or inclined to one another. In either case the top tube or tubes will be the top part of the frame, the side tubes will be the side parts thereof and the cross-tubes will be the cross parts. Their relation to each other and action in the frame would manifestly be the same if made solid instead of tubular; but a tubular frame is preferable for the combination of v lightness and strength.

I claim- 1. A motorcycle frame provided with a longitudinal top part and two longitudinal extending divergently downward to a plane Y lower thanthe operating machinery and laterally beyond the same and having middle parts widely'separated by substantially parallel parts for lessening friction as set forth when the motor cycle turns over oneither 1 side.

3. A motorcycle frame provided with a longitudinal top part and two longitudinal side parts extending downward and outward therefrom and cross parts connecting and bracing at intervals said side parts, the said side parts being constructed for the motorcycle to slide partly on one or the other of them for lessening friction when the motorcycle is overturned on either side.

4. A motorcycle frame comprising a longitudinal top tube and two longitudinal side tubes rigid therewith, said side tubes diverging outward and downward at bothends of the frame and havingv integral parallel middle parts outside of the operating mechanism and with a wide interval between them,

in order that the motorcycle may slide on outside of the operating mechanism adapted one or the other of them, thus lessening fricto prevent any part of the machine from tion, if it be overturned on either side. contact with the ground in case it should 5. A motorcycle frame comprising a lonturn over on either side, except the wheels gitudinal top part, two longitudinal side and one of said skids. parts, a head lug connecting said top part 7 A motorcycle frame having two lateral and side parts at one end of the frame, and longitudinal skids adapted to prevent any a seat lug provided with a cross part conpart of the machine from contact with the necting said top part and side parts at the ground except the wheels and one of said other end of the frame, said side parts he skids, in case the machine should turn over ing bent laterally in opposite directions, exon either side, said skids being provided tending downwardly and provided with with a shield which covers the bottom and widely separated substantially parallel midsides of the space between them to protect dle portions, one of which will act as a skid the operating mechanism. in case the motorcycle should overturn on 8. A motorcycle frame having two lateral either side, preventing the contact of any longitudinal skids substantially as described part of the machine with the ground except and provided with a shield below the operthe wheels and said skid. ating mechanism, in which shield two tool 6. A motorcycle frame comprising a lonboxes are formed, their lids serving as footgitudinal top part, two longitudinal side boards. parts connected therewith and two main- In testimony whereof, I have signed my stays extending rearward from said side name to this specification in the presence parts to support forks for the rear wheel of of two subscribing witnesses.

the machine, said side parts forming skids GRANVILLE EASTWOOD BRADSHAW. 

